Apple has released the first major software update for the iPad. The 4.2 version of iOS brings a slew of new capabilities to the iPad, including many that will be of interest to business professionals and to IT departments that have deployed or are considering a deployment of the iPad.

The update, which is available as a free download through iTunes, is the first jump to iOS 4 for the iPad. The iPhone got iOS 4 in the spring but the iPad has been stuck on iOS 3.2 until now. With iOS 4.2, the two devices are now unified on the same operating system (along with the iPod Touch as well).

Below is my list of the 10 most important iOS 4 updates for iPad business users, along with my screenshot gallery that gives you a quick peek at the new features.

Screenshot gallery

1. Multitasking

The biggest factor holding back the iPad has been its lack of multitasking. With the 4.2 update, multitasking has finally arrived. It works the same way as iPhone multitasking, which arrived earlier this year. To be clear, iOS 4.2 multitasking is actually more like quick-switching between apps while saving the state of open apps. But, at least it changes the iPad from being a one-app-at-a-time experience. This is especially important for workers who need to copy-and-paste between apps and do other types of multi-app integration. To access multitasking you simply double-click the home button.

2. AirPlay

AirPlay is the flashiest new feature in iOS 4.2. It allows you to quickly stream media from an iPad (or iPhone or iPod Touch) to an Apple TV. The functionality is in its infancy and it may not sound like it has much use for business, but it could be huge. Today, once you have video or photo open, it only takes two taps to throw it up on the big screen. Plus, you can almost-instantaneously switch between different presenters. In the future, imagine hooking up an Apple TV — a tiny $99 box not much bigger than a smartphone — to a projector or a 60-inch LCD TV in a conference room and being able to quickly and easily share charts, graphs, media clips, and presentations straight from your iPad. Look for lots of apps to find ways to take advantage of AirPlay.

3. Wireless app distribution

With 4.2, enterprises can push out their own custom business apps to corporate iPad users over Wi-Fi or 3G. The apps don't have to go through the Apple App Store and users don't have to sync through iTunes or a computer in order to get the company apps.

4. AirPrint

Another one of the most talked-about features of 4.2 is AirPrint, which lets you print wirelessly from the iPad. The implementation on this is pretty good. A print option is added to the menu for printing documents, photos, and web pages and the iPad automatically recognizes compatible printers nearby. Unfortunately, the list of compatible printers is very small for now, and apps will need to add this functionality to their software so that printing will be possible in more places on the iPad.

5. Find My iPad

This was previously part of Apple's paid MobileMe service but with iOS 4.2 it is now a free option. Once you activate this on your iPad you can go to the Apple website to locate your lost iPad on a map, send a message to display on the iPad screen ("I lost my iPad, please call 987-654-3210"), set a remote passcode to lock out prying eyes, or even remotely wipe the device and all of its data.

6. Folders

You can now create folders on the iPad to organize your apps into groups, tuck away the apps you don't use as often, and save yourself from having to flip through an endless number of screens to find the app you're trying to locate.

7. Unified inbox

The Mail app offers an improved interface that reminds me of the terrific email functionality on the Palm Pre. It gives you a quick jump directly to the inbox (new messages) of each of your multiple email accounts, or to your list of folders for those email accounts, or into a unified inbox where you can see all of your latest messages threaded together by timestamp. The 4.2 upgrade also now supports multiple Microsoft Exchange mailboxes.

8. Remote device management

Another development on the enterprise front is that the 4.2 upgrade offers Mobile Device Management APIs that allow companies to wirelessly push out configuration changes, monitor compliance with policies, and lock or wipe an iPad managed by the IT department. These features are aimed squarely at the companies deploying fleets of iPads to workers.

9. Web browser search on page

The web browser on the iPad has always had a search box for searching the Internet, but now Apple has added functionality to that box that allows you to use it to search for text on the current web page as well. This is especially useful when you do a web search and land on a page but can't find the reference to the keyword you were looking for.

10. New quick controls console

If you click the Home button twice to go into multitasking and swipe to the panel on the left you'll find a new quick control console that has a play/pause button and forward/back buttons for the iPod app, a volumne control slider, a brightness slider, and a new virtual orientation lock setting. The old physical orientation lock button (on the right side above the volumn buttons) has now been converted into a mute button.